1. Field of the Invention
The present invention relates to a downgrade memory apparatus and a method for accessing a downgrade memory. More particularly, the present invention relates to a downgrade memory apparatus capable of recording bad sectors in a block.
2. Descriptions of the Related Art
Usually, memories may have some defects during manufacturing. The defected memories would be sifted out from qualified memories during a quality control process, and are not applied in markets. However, the defected memory is still used well by a specific procedure. The defected memory may as well include some defects as be reused. Such memory is called a downgrade memory.
The aforementioned defects including defected blocks that cannot be accessed, defected connection between elements of the memory, and etc. Once a memory is determined as a downgrade memory during manufacturing, the downgrade memory may be dumped and the cost of products increases. However, some downgrade memories only have few defects and still good at most parts thereof. For example, a downgrade memory may be designed to have 1 Giga bits, but actually only has 600 Mega bits accessible space. Once the downgrade memory is dumped, then the 600 Mega bits accessible space is wasted.
Therefore, the memory industry is desired to utility the downgrade memory by enhancing accessible resource of the downgrade memory to achieve well use of the defected memories and to decrease production cost.